Securing the Internet of Things - or how light bulbs can spy on you

Analysis It's going to be a tough task securing the Internet of Things, an upcoming massive global network of web-connected fridges, freezers and pacemakers. But according to experts gathered in Cambridge last week we can't even start locking it down until we know who's going to make money from it.

The meeting was run by Cambridge Wireless, and attended by luminaries from all the important companies hoping to cash in on the Internet of Things. They came to hear talks from chip designers CSR and Nordic Semiconductor, and the usual round of consultants. The confab focussed on how 50 billion devices could be wired up to the public internet by 2020 and how they will be protected from the legions of ne'er-do-wells poised to hijack light switches and washing machines around the world.

At a basic level, securing those devices will involve cryptographic keys and authentication mechanisms, such as those made by Nordic Semiconductor which explained how its own embedded security had evolved.

But security is more than cryptography; equally important are architectures capable of distributing data while maintaining the owner's control over the distribution, and ensuring services aren't locked to suppliers, all of which will depend almost entirely on how companies decide to make money from the idea.

Millions and millions of things talking to each other without a business model between them

If one accepts that 50 billion devices are going to be connected, and that a significant proportion of those devices are going to be in our homes (as opposed to traffic lights, parking meters or cow bells) then we need to establish if those light switches and smart fridges are going to connect straight back to their preferred cloud or whether the data will be aggregated at a home hub.

The former is simpler, but the latter permits analysis by the residents, who will be able to decide which streams of information are passed to which services, and may be legally mandated across the European Union at least. This will be in a world in which light bulbs report that they've been left on all night to power giants, and fridges let your supermarket's warehouse nightshift know when you're about to run out of chocolate body spread.

Liz Fitzsimons of "legal innovators" Eversheds explained the legal responsibilities involved. The latest European privacy directives may require that sensors around our homes ask our permission before phoning home, not only to prevent illicit data gathering but also allowing us to take our data elsewhere if we sign with another provider - redirecting the readings from our smart electricity meter to a company that won't switch it off in the middle of EastEnders, for example.

Those controls would probably fall to the home hub, but there aren't any standards by which such a device could operate so one could end up locked to a proprietary hub instead of a service.

There's a comparison to apps here, though not enough to justify the term "appcessories" which was banded about Internet of Things celebrity Nick Hunn. A smartphone can have dozens of applications installed, most of which have the authority to contact a cloud whenever they want to share data of all sorts. Users seem quite comfortable with that, but regulators are becoming more interested and when the same things starts happening with hardware it becomes more of an issue.

Those regulators are ready to fight too; updates to EU law will allow states to fine a company up to two per cent of its global revenue if it's caught slurping data without permission.

Hunn pointed out that even a smart meter of limited intelligence can identify larger household appliances, such as an electric shower, while a water meter can tell you if anyone's home with some accuracy - so security of that data is important. Determined and suitably tooled-up eavesdropping burglars will be lured to properties that advertise themselves as temporarily unoccupied.

Current thinking is that cryptographic keys distributed by the supplier will secure the data end-to-end, but that would mean an irritating change of meter with every change of supplier at a time when customer choice is supposed to be paramount.

Smart meters are supposed to make changing suppliers easier. The enormous cost is, in part, justified by their ability to drive down prices by increasing competition.

What happens when clouds of sensitive data collide

Data from the device doesn't have to be encrypted just once and then sent all the way to the cloud; the flow of information can be segmented and protected within these shorter paths. This allows the data to be secured between just the device and a home hub or another trusted third party called a security manager. The hub and security manager can encrypt the data again after deciding which cloud service will receive the information.

A security manager in this case is a server defined by the Weightless Special Interest Group (SIG). These guys are the brains behind the Weightless machine-to-machine communications standard, which will initially operate in White Spaces - the chunks of radio frequency now free to use after the death of analogue TV.

Weightless-compatible devices chat to each other and their manager in their own separate network, and are not reliant on a home hub nor a broadband connection. The manager could be run by a network provider, a hardware manufacturer (say, Bosch), a utility (such as Scottish Power) or the Weightless SIG itself.

A Weightless-SIG-hosted security manager passes device data to the company providing the service (be that Scottish Power or whomever) and take instructions from the user if he or she wants to change providers.

When it comes to the cryptography itself, Nordic Semiconductor's Daniel Ryan explained how its communications chips had evolved; security is a secondary feature of the short-range radio electronics made by Nordic for numerous computer keyboards and mice.

Early versions simply had a crypto-key stored in the wireless keyboard and the USB receiver dongle; bytes of data representing the key presses were trivially XORed with the key to obfuscate the transmission, a solution which was both expensive and insecure. The next version added a counter, to prevent replay attacks, and used AES rather than XOR, but it still required unique keys to be programmed into the devices at manufacture (an expensive process) and was vulnerable to analysis given the non-random nature of typed text.

The third design requires the keyboard to generate a random crypto-key for each dongle it talks to; before this key is sent to the receiver, it is encrypted using a secret common to all of Nordic's Gazell chips. That shared secret is never used again between the keyboard and the dongle; the now randomly padded communication is subsequently encrypted with the new key, which is remembered by the keyboard and the dongle forever. For complete security a PIN is added during pairing, and the transmission power is turned down during pairing to reduce the chance of being sniffed. Lastly, the source code for the whole lot has been thrown open for public scrutiny.

Those changes aren't all in response to customer requests, or hack attacks, but were put in place in an attempt to build confidence in the security of the product even if incidents of wireless keyboard sniffing are all but unknown. It would only take one public case to dent that trust, perhaps fatally.

Mandated data protection, coming to a light bulb near you

The R&TTE regulations, required for the CE mark, already request that manufacturers "incorporate ... safeguards to ensure that the personal data and privacy of the user and of the subscriber are protected", but drafted updates turn that request into an obligation. Thus, cryptography will be mandated in any of the 50 billion things used by people or households (as opposed to cows, sheep, streetlights, etc).

But the big question which remains is how it's all going to be paid for, which in turn defines the architecture and thus the security that can be applied.

The manufacturer of a boiler might add a lifetime's cloud support to the price of its product, but as CSR's Robin Heydon pointed out, when one's thermostat checks the weather forecast from Accuweather it's not going to see the advertising that pays for the service, so machines will have less free data to work with than their eyeball-touting masters.

ISPs might start selling smart hubs that aggregate data for transmission, but today's heating and lighting systems are built into houses well before the ISP has been selected, so cloud-based management of Hue lightbulbs or Nest thermostats will need to be transferable between owners and service providers.

All this is predicated on the assumption that our homes are going to become hives of connectivity with machines chattering away to each other day and night, sometimes saying nothing at all other than a "hello, world" just to make sure robbers don't take the lack of network traffic as an indicative of our absence.

If we ignore the Internet of Things, pretending it's not going to happen, then likely it will emerge through mandated smart meters and kids' toys. Only then it will come without the privacy safeguards, owner's control and security which the chaps and chapesses in Cambridge spent so long debating. ®